Apparatus for rendering a protective device responsive to phase relations.



1,211,000, Patenied Jan. 2,1917.

P e/ nnlunn fake UNITED STATES PATENT OFFICE.

SEVEBN D. SIRONG AND WALTER E. McCOY, OF NEW YORK, N. Y.

APPARATUS FOR RENDERING A PROTECTIVE DEVICE RESPONSIVE TO PHASE RELATIONS.

To all whom it may concern Be it known that we, SEVERN D. SPnoNo and IVALTER E. MCCOY, citizens of the United States, residing at New York, in the county of New York and State of New York, have invented a certain new and useful Improvement in Apparatus for Rendering a Protective Device Responsive to Phase Relations, of which the following is a specification.

The invention is an apparatus embodying our method of rendering a protective device responsive to changes inphasc relations, which method consists in establishing phase relations substantially 180 producing substantially no flux under nor mal conditions between two circuits normally out of phase, and each including means for generating mutually counteracting forces, whereby the said. translating device is controlled by the unbalancing of said forces due to disturbances in the said estab lished phase relations. \Ve may apply this method in many devices, and for a great variety of utilizations. In our present appa ratus, the object. is the protection of a polyphase motor against damage due to open wires or phase reversals, and the said apparatus is constructed so that a disturbance of phase relations between or the opening of either of the two circuits effects the blowing of a fuse in a relay circuit including the no-voltage release coil of a switch or circuit-breaker, thereby dei nergizing said coil and permitting the switch to open circuit to the motor.

In the accompanying drawings Figure 1 is an electrical diagram, showing our apparatus. Figs. 2 to 9 are electrical diagrams illustrating certain principles underlying the same. Fig. 10 is an electrical diagram, showing the apparatus of Fig. 1 applied to a poly-phase motor to'be protected. Fig. 11 is a detailed diagrammatic view of the fuse and contact linger.

Similar letters and numberso'f reference indicate like parts.

The apparatus shown in Figs. 1, 10 and 11 consists in a shunt transformer, whereof 1 and 2 are primary coils connected to opposite phases of the two-phase three-wire supply circuits 3, 1, 4 and 5, 2, 4, through a non-inductive resistance. 6 and a rcactance 7.

The relative values of the said resistance and reactance are to be such that when the Specification of Letters Patent.

Application filed March 2, 191a.

apart, and thus Patented Jan. 2, 1917. Serial No. 81,626.

coils 1, 2 are connected in said circuits, wherein the phase relations are normal, the currents in said coils 1, 2 shall be equal in value, and in opposition. In such case, no voltage is induced in the secondary coil 8 of said transformer. The terminals of said secondary coil are connected to the terminals of a fuse 9, Fig. 11, upon the bodyof which fuse bears a movable contact finger 10, to which one terminal of a relay circuit 11 is connected. The other terminal of said relay circult 18 connected to one of the fuse terminals. In said relay circuit may be inmaining energized coil in the secondary coil- 8 to blow the fuse 9, thus interrupting the relay circuit, deenergizing the release coil 12, and permitting the switch 13 to be retracted by its springs, indicated at 15.

In Figs. 2 and 3 we have illustrated graphically the current conditions in our apparatus for two and three-phase circuits. In Fig. .2, which relates to two-phase circuits, the line A, B represents the current in phase with the impressed voltage across the primary coil 1 in series with the noninductive resistance (3. A, C represents the voltage across the primary coil 2 in series with the reactance 7. By reason of tlie reactance. the current in coil 2 lags 90 d grees behind its impressed voltage and takes the position A, D, approximately 180 degrees from A, B. In Fig. 3, which applies to three-phase circuits, the line A, B represents the current in phase with the impressed voltage across the coil 1, and A, C represents the current in phase with the impressed voltage across the coil 2. The current in the coil 2 lags degrees behind its impressed voltage and takes the position A, D, approximately 180 degrees from A, B. Under these two normal operating conditions there will be a small resultant current A, E in the secondary 8 of the transformer, but this will be of sufficiently low value as not to blow fuse 9. Either coil or may become operative to induce current in the secondary by reason (a) of an interruption in the circuit 3, 1, i or 5, 2, 1 including that coil, or (b) when a change occurs in the plies: or 5, 2, l respectively including said coils.

(o is obvious that it the current in either coil 1 or coil 2 be interrupted, the

relations of the circuits 3, l, l

where due to the reactance in series witli' the transformer winding ih,0, a result-ant current A, E is produced of suliicient magnitude to melt the fuse. I

, it having thus been shown that the fuse 9 will be melted in the event oi any phase reversal, or in case either supply circuith coniesopen, the resultant operation of the switch or circuithreal;er insures positive remaining coil will continue to he energized, protection to the translating device against and hence, as already stated, will induce suflicient current in the secondary coil 8 to blow the iuse 9. The apparatus is thus operative on single phase circuit.

(5')) In 5, and c, We illustrate conditions when by reason of a change in. the normal phase relations, indicated in Fl 5. 2 and 3, a current is induced in the secondary 8 suiiicient tohlow the fuse 9 and open therelay circuit 11. the case oi a two-phase three-Wire circult, only one of possible conditions will produce the normal condition, 2. Under any other than the normal condition, the resultant current A, E, Figs. and 6, is su'fiicient to melt the fuse. in Fig. i the two leads 3, 5 are assumed to he crossed, 1e reactance is in the leading phase and the resistance in the lagging phase.

in 6 a potential lead, as 3 or 5, and the neutral lead 4 crossed, the reactance phase and the re the potential leads.

now being in. the

ince bet acro chase fou -Wire interconnected circuits possible combinations, och will produce rotation. @f

., these tour are'normal and lour abnormal, illustrates the normal phase relation in this type oi circuit, and

shows any of the abnormal conditions which will produce rotation and under which the current A, "will blow interconnectedcirc 8 and ll n I the phase relations under the condi till 'tions which will not produce rotation, but

ate, e the voicel ss A c and A. B

1 Y in 9 7 7 mot coils,-the said controlling device shall. be

operated by the current induced on said secondary,

2. i-ln apparatus for rendering a protective device responsive to changes in. phase relations, comprising primary formed oil two counter-balancing cells, a. secondary, a circuit including said. secondary, and means for opening said circuit operated. by the current induced on said secondary Whensaid current shall have attained a predetermined value.

3. An apparatus for rendering a protective device responsive to changes in phase relations, comprising a primary formed of two counter-balancing coils, a secondary, a circuit including :said secondary, a no-voltage release magnet in said circuit, and a switch lever controlled by said magnet, and a translating device in relay circuit with said switch let er.

a. An apparatus for rendering a protective device responsive to changes in phase relations, comprising; a primary formed of two counter-l ala'n.cing coils, a secondary, a circuit including said secondary, a fuse said ci cuit, and a translating device in re lay ci' uit with fuse.

5. An apparatus for rendering protec tive device responsive changes in phase relations, comprising a primary termed ct two counter-balancing coils, a secondary, a

a proteccircuit connected to one of said fuse terminals and to said spring arm, and a transiating device in. said relay circuit.

7. A protective apparatus for a polyphase motor, comprising a supply circuit therefor, two circuits in shunt with said supply circuit and receiving, different phase current therefrom, two primary coils respectively disposed in said phase circuits and connected in opposition, a secondary,

a fuse in circuit with said secondary, and

a relay circuit including said fuse and .said motor.

8. A protective apparatus fora polyphase motor, comprising a supply circuit -therefor, a switch in said circuit, a no-volt- Witnesses:

GERTRUDE T. PORTER, MAY MGGARRY. 

